Large networks are often organized to enhance security from outside attack. A common architecture for such a network includes a perimeter network, or DMZ (i.e., demilitarized zone), that surrounds a trusted network and acts as a buffer between the trusted network and the broader (e.g., global) computing network. These perimeter networks are utilized as a first line of defense against attack from entities residing in the broader network. As a first line of defense, devices and data stored upon the perimeter network are assumed to be at greater risk of attack. Thus, network designers carefully consider what data is placed on devices residing in such perimeter networks. For example, a common task for servers placed on a perimeter network is the routing of e-mails to users within the trusted network. To perform such routing functions, these servers need some information related to the users on the trusted network. Such data is readily available on the trusted network, such as through a distributed directory service containing configuration information (e.g., Microsoft Windows® Active Directory for Windows Server 2003). But because of the increased vulnerability of the perimeter network servers to attack, it is advantageous to limit the quantity and type of data replicated from the distributed directory service on the trusted network and placed upon the perimeter network servers. For the e-mail routing example, e-mail addresses may be stored on servers in the perimeter network, while other information about users is stored on the distributed directory service of the trusted network.
Propagating such data from the distributed directory service on the trusted network to servers on the perimeter network is performed manually by some systems because the security mechanisms between the trusted network and the perimeter network are configured differently and do not allow such communications. In many cases, an administrator will physically transport such data from a trusted network computer to a perimeter network computer with a portable memory device. This process is time-consuming, slow, poses other security risks, and is generally undesirable. A system for automatically sending configuration information from the trusted network to the perimeter network would be useful.
For such a system to function robustly, servers located on the trusted network should communicate readily with servers on the perimeter network. For example, a particular trusted network server could be assigned to service one or more perimeter network servers. Such a system, however, would be susceptible to inoperativeness if one or more of the trusted network servers or perimeter network servers become non-functional. For example, if the trusted network server becomes non-functional (e.g., for servicing), the network server can no longer send updated configuration information to the served perimeter servers. Moreover, changes in the status of one or more of the servers on the perimeter network should be addressed. In these situations, communication paths may become unusable. For each of these situations, therefore, a system that is capable of adapting to particular computing devices becoming unavailable by utilizing other devices for communication would be useful.